Battery charging control device



Filed Jan. 28, 1942 un@ will!" "if Y /8 1 wie 39 en f2 if* w 42 Q L Y 44v y e 44 sal* "9 |A G l@ IIIInmmm|II|u|luu||||||||||||||||u|m||||||||\ X34 5 7 36 y Inventor: Louis W. Thom son,

b .Wa/Wij y His Attorney.

Patented Qct.l 26, 1943 UNITED BATTERY CHABGING CONTROL DEVICE Louis W.Thompson, Schenectady, N. Y., assignor to General Electric Company, acorporation oi.'

New roi-k Application January 28, 1942, Serial N0. 428,474

(Cl. y1'11314) Z Claims.

My invention relates to battery charging control devices and has for itsobject a reliable and inexpensive battery charging device and means forrendering the device unresponsive to close the charging circuit in theevent of reversed polarity of the generator.

In carrying out my invention in one form I providevan electric valve incircuit with the voltage coil of the device whereby the coil isenergized in response to the voltage of the generator when the polarityof the generator is correct and whereby no current is supplied to thecoil and the coil is not energized in the event of reversed polarity ofthe generator.

For a more complete understanding o my'invention, reference should behad to the accompanying drawing in which Fig. 1 is a side elevation viewof a battery charging control device embodying-my invention; Fig. 2 is aplan view of the device shown in Fig. 1 with the cover removed; Fig. 3is a simplified exploded view of the parts of the device connected in abattery charging circuit; while Fig. 4 is a diagram of connections ofthe battery charging system embodying my invention.

Referring to the drawing, particularly Fig. 4, in one form of vmyinvention the charging direct current electric generator I driven by asuitable means (not shown), such as the axle of a railway car on whichthe generator is mounted, is electrically connected in circuit with theelectric storageAbattery II which is to be charged by the generator.This charging circuit leads from the generator through the battery II,the conductor I2, charging switch I3, the current coil Il and theconductor I5 back to the other side of the generator. The switch I3 isbiased to its open position and is moved to its closed circuit positionby means of a coil I6 connected across the generator I0 through a relaycontrol switch I1 which is operated by the joint action of the currentcoil l'and a generator voltage responsive coil I8.

This coil I8 has one terminal connected to the battery charging circuiton one side of the switch I3 so that it is connected through the currentcoil I4 and the conductor I5 directly to one side of the generator. Theother or upper` terminal of the coil I8 is connected through a currentlimiting resistance I9, an electric valve 20 shown as a copper oxiderectifier, and conductor 2| directly to the other side of the generator.

Thus in the operation of the system, assuming that the generator speedis so low that its voltage is' below the required battery chargingvoltage and that the switch I3 is open, when the speed o! the generatorincreases so that its voltage reaches a predetermined generator chargingvoltage. the coil I8 connected across the generator is energizedsuiliciently to pick up its armature and close the control switch I1.This connects the coil I6 directly across the generator and the coil I6thereupon closes the switch I3 for completion of the battery chargingcircuit.

It will be understood that the electric valve 20 is connetced in thecircuit in such direction that it passes current through the coil I8 in`response to a generator voltage of the predetermined battery chargingpolarity. In the event, however, that thegenerator voltage becomesreversed in polarity, which might result from a reversal of itsdirection of rotation, the valve 20 does not pass current to the coil I8and, consequently, the control switch I1 remains open regardless of thevalue of this reversed generator voltage.

During the charging of the battery, the relay switch II is maintainedclosed by the combined effect of the voltage coli I8 and the currentcoil Il which acts cumulatively with respect to the voltage coil. In theevent that the generator voltage decreases to a value lower than thebattery voltage, the battery discharges through the generator therebyproducing a reversed current in the coil I4 which thereupon opposes thevoltage coil I8 and causes the switch I'i to open for deenergization ofthe coil I8 and opening of the switch I3 whereby the battery isdisconnected from the generator.

In the event that the voltage of the generator becomes reversed for anyreason, as by the reversal of its field or the reversal of its rotation,the voltage coil I8 ls not energized because the valve 2li is connectedto prevent theow oi current of any value sumcient to cause the closureofthe switch I1 in response to a voltage or that reversed polarity.Therefore, the relay switch Il can not close in response to thisreversed voltage and thecharging circuit remains open.

As shown in Figs. l, 2 .and 3, the control device is mounted on a base2l made of electrically insulating material. The two terminals of thecharging generator I0 are connected by suitable conductors to thebinding posts 23 and 24. One terminal of the generator, preferably thenegative terminal, is connected to the control binding post 25 which isconnected through an electrically conducting and supporting plate 26 tothe copper oxide rectier 20, the opposite terminal of which is connectedto one side of the resistance I9. As

shown, the resistance I3 is of a type having its resistance surroundedand sealed by a layer 21 of refractory electrically insulating materialsuch as porcelain or glass, the resistance being cylindrical in shape.The two terminals 23 and 29 of the resistance project from one side. Oneof these terminals 28 is connected through a conductor 30 (Fig. 2) to aplate 3| forming one terminal of the rectiiler 20. The other terminal 29of the resistance is connected through the conductor 32 to one side ofthe voltage coil i8, the other side of which is connected through theconductor 33 to the point 34 on one of the stationary terminals 35 ofthe switch I3. A similar second stationary terminal 36 is provided inspaced electrically insulating relation with the terminal 35.

These switch terminals are mounted on suitable electrically insulatingsupports on opposite sides of the iron core member 31 for the coil I6 inelectrically insulated relation with the core member 31 and with eachother. This core member 31 forms part of a magnetic core extendingthrough the oil I6 and connecting at the upper end of the coil as seenin Figs. 1 and 2 with an L-shaped magnet core member 38. The other endof the core member 38 carries a U-shaped bracket 39 between the sides oiwhich an armature member 40 is pivotally mounted yat an intermediatepoint of the armature member. A helical spring 4| mounted in a tubularsupport 4Ia `on the core member 38 bears on the amature 40 and biases itin a counterclockwlse direction, as seen in Fig. 3, to the positionshown.

On the lower end of the armature 40, as seen in Figs. 1 and 2, aremounted two bars 42 and 43 which constitute electric bridge members forelectrically connecting together the terminals 35 and 36. It will beunderstood that these bridging members 42 and 43 make electric contacteach at its respective ends with electrical contacts on the terminals 35and 36. I'he bridging member 42 has much greater cross section than themember 43 and hence much greater current carrying capacity. It is somounted as to engage its stationary contacts after the smaller bridgingmember 43 engages its contacts to establish a circuit. In other words, abridging circuit between the contacts 35 and 36 is always initiallyclosed or opened through the bridging member 42 which has a smallercross section and therefore a higher electric resistance as comparedwith the member 42. This arrangement serves to prevent; arcing andwelding of the contacts. The two bridging members are held resilientlyagainst the end of the armature 40 by a helical spring 44.

'I'he supporting plate 26 of electrically conducting material is securedas shown to an upwardly extending portion 44a made of electricallyinsulating material secured to the base 2|. Also as shown, the bindingDOsts 23 and 24 are secured to this portion 44a. In addition to formingan electric conductor, the plate 26 acts as a supporting bracket for thecopper oxide electric valve 20 and for the resistance I9. As shown, abolt 45 extends through the copper oxide rectier and the resistance I 9,it being provided with two clamping nuts 46 and 41. Thus the nut 46 isturned tight against the copper oxide rectiiler to secure its platestogether, there being a copper oxide rectier washer 45 with anelectrically conducting washer on .each side of it and these threewashers'being clamped between the plate 26 and the plate 3|. Thus theplates 26 and 3| form terminals for the copper oxide rectiier. These twoplates 25 and 3| are provided with enlarged openings through them forthe bolt 45. openings of similar size being provided in the copper oxiderectifier washers, and a cylindrical bushing (not shown) made ofelectrically insulating material is mounted on the bolt so as t0 extendthrough the copper oxide rectiner washers and the enlarged holes in theplates 25 and 3|. Also, washers 43a and 43h made of electricallyinsulating material are provided on the outer sides of the plates 25 and3|, and the cylindrical insulator (not` shown) around the bolt 45extends through these two insulating washers. Thus with thisconstruction the bolt 45 is electrically insulated from the plates 2land 3l and from the rectiiier discs between the plates. These parts areclamped together by the nut 45 on the bolt.

The resistor I3, as previously stated, has its resistance conductorembedded in electrically insulating material and it is provided with acentral longitudinally extending aperture through. winch the bolt 45extends in electrically insulated relation with the resistor. The nut 41is clamped firmly against the outer end of the resistance so as tosecure it between the two nuts.

As shown in Figs. 1 and 2, the voltage coil I8 and the current coil I4are mounted on two core members extending through them and magneticallyconnected together by means of a plate 43 made of magnet core materialto form a U-shaped magnet. This magnet operates an armature 43 pivotedcentrally on a bracket 5|) which is secured to the top of the coremember 50a. Adjacent the other end o! the armature 49 is carried amovable contact 5| which cooperates with a stationary contact 52 carriedby the conducting support 25. As a magnet core material I preferably usea low magnetic residual material, such as an alloy of nickel and iron.

An electrical connection for the movable contact 5| is made by aconductor 53 having one end connected to a bracket 54 which is mounted Yon the plate 48. The other end of this conductor 53 is connected toanother terminal (not shown) just behind the terminal 25, as seen inFig. 2. This terminal (not shown) is connected to the side of thegenerator opposite that side ,to which the terminal 25 is connected.Thus the movable contact 5| is connected in an electric circuit throughthe conductor 53, the bracket 54, the plate 48, core member 50a andbracket 50, tolthe armature .45.

The bracket 54 forms afstop for the upper end of the armature 49, asseen in Fig. 1, a disc 55 of electrically insulating material beingsecured to the end of the bracket so as to be engagd by the end of thearmature 49 when the armature is pulled to its unattracted position bymeans of the biasing spring 56. An adjustment is provided for thetension of this spring 56 consisting of a U-shaped strap 51 having oneend secured to the magnet plate 48 and its other end to which the spring56 is secured adjustable by means of a screw 5B.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto, sincemany modiiications may be made and I therefore contemplate by theappended claims to cover any such modiiications as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent lof theUnited States is:

1. Thecombination with a generator of storage battery, a normally openload switch for connecting said battery to said generator for chargingof said. battery. an operating coil for said load switch, a normallyopen relay switch in circuit with said operating goil, connectionsconnecting said operating coil through said relay switch across saidgenerator, a voltage coil for operating said relay switch', a copperoxide rectier, electric connections connecting said voltage coil andsaid copper oxide rectifier in series with each other across saidgenerator, said copper oxide rectifier being connected with'a polaritysuch as to pass current and energize said voltage coil in response to agenerator voltagel of a predetermined :battery charging polarity andsaid voltage coil being arranged to close said relay switch in responseto a predetermined value of said generator voltage whereupon saidoperating coil is energized and closes said load switch, said copperoxide rectiiier preventing the energizatlon of said voltage coil in theevent of reversal of the voltage of said generator, and a current coilfor said relay switch connected in circuit with said generator vin adirection to be cumulativewith respect to said voltage coil in responseto a battery charging current but bucking said voltage coil to open saidrelay switch upon the occurrence of a reverse generator current of apredetermined value.

u 2. A battery chargingV controlv device coinprising an electricallyinsulating hase, a normally open charging switch on said base, anoperating coil on said base for operating said charging switch to itsclosed circuit position. a relay switch in circuit with said operatingcoil,

a voltage coil for operating said relay switch,

na terminal plate of electrically conducting material secured to saidbase, a copper oxide rectier disc having a central aperture, a secondterminal plate, said plates being provided with apertures, a cylindricalresistance having a central aperture a clamping bolt extending throughthe apertures in said terminal plates, said rectiiier disc and saidresistance,`means electrically insulating said bolt from said parts,said bolt clamping said terminals and said copper oxide disc together toform a copper oxide rectifier supported by said rst terminal plate, andsaid bolt securing said resistance to said rst terminal plate, andelectrical connections connecting with said terminal plates and theterminals of said resistance thereby to connect said rectier and saidresistance in series with each other in the circuit of said voltagecoi1.

LOUIS W. THOMPSON.

